Production of branched chain paraffinic hydrocarbons



Patented @ec. 31, 1946 PRODUCTION OF BRANCHED CHAIN PARAFFINIC HY DRO CARB ON S Louis Schmerling, Riverside, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a

corporation of Delaware No Drawing. Application January 27', 1944, Serial No. 519,910

11 Claims.

This invention relates to reaction of a paraffinic hydrocarbon of relatively low molecular weight with an alkyl halide containing at least 6 carbon atoms per molecule and in the presence of a catalyst of the Friedel-Crafts type.

An object of this invention is the production of a branched chain paraffinic hydrocarbon by causing reaction of an alkyl halide containing at least 6 carbon atoms per molecule with a parafiinic hydrocarbon containing at least 4 and not more than 5 carbon atoms per molecule in the presence of a catalyst of the Friedel-Crafts type.

Another object of this invention is the producticn of branched chain ,paraffinic hydrocarbons by reacting, in the presence of a Friedel-Crafts type catalyst, an isoparafiinic hydrocarbon containing not more than 5 carbon atoms per molecule and an alkyl halide containing at least 6 carbon atoms per molecule.

A further object of this invention is the production of a parafiinic hydrocarbon containing at least '6 carbon atoms per molecule by reacting a paraflinic hydrocarbon containing at least 4; and not more than 5 carbon atoms per molecule in the presence of acatalyst of the Friedel-Crafts type with an alkyl halide containing at least 6 carbon atoms per molecule, the alkyl halide being converted into branched chain parafiinic hydrocarbons containing at least 6 carbon atoms per molecule.

Qne specific embodiment of the present invention relates to av process for producing branched chain paraffinic hydrocarbons containing at least 6 carbon atoms per molecule, and comprises reacting analkyl halide containing at least 6 carbon atoms per molecule with an i oparamnic hydrocarbon containing not more than 5 carbon atoms per molecule and in the presence of a catalyst of the Friedel-Crafts type.

A further embodiment of the present invention relates to a process for converting a parafiin containingat least 4 and not more than 5 carbon atoms per molecule into branched chain parafilnic hydrocarbons containing at least 6 carbon atoms per molecule and comprises reacting said paraflin in the presence of a catalyst of the Friedel-Crafts type with an alkyl halide containing at least 6 carbon atoms permolecule, the alkyl halide being simultaneously converted into branched chain hydrocarbons containingat least 6 carbon atoms per molecule.

Parafiinic hydrocarbons utilized in the present process contain at least 4 and notmore than. 5 carbon atoms per molecule. ,I prefer, however,

to employ isobutane and isopentane in the present process for converting alkyl halides containing 6 or more carbon atoms per molecule into parafiinic hydrocarbons.

The primary, secondary, and tertiary alkyl halides utilizable in this process may be obtained from any source. Furthermore, they are not necessarily employed under the same conditions of operation in the presence of the alternative isoparaifinic hydrocarbons and different catalysts of the Friedel-Crafts type.

Alkyl halides which I prefer to use in my process contain 1 halogen atom per molecule and said halogen atom has an atomic weight of between about 35 and 80. Some of these alkyl halides are produced by reacting a mono-olefinic hydrocarbon and a hydrogen halide, such as hydrogen chloride or hydrogen bromide, preferably in the presence of a catalyst, such as a metal halide of the Friedel-Crafts type, a mineral acid, or another acid catalyst. Addition of a hydrogen halide to an olefin results in the production of tertiary alkyl halides from tertiary olefins and of secondary alkyl halides from non-tertiary olefins containing 6 or more carbon atoms per molecule. Tertiary alkyl halides also action of a tertiary alcohol and a hydrogen halide. Primary alkyl halides, also utilizable in the present process, are obtained by other means such as by the treatment of a primary alcohol with a hydrogen halide such as hydrogen chloride or hydrogen bromide in the presence of a suitable catalyst. Primary alkyl bromides may be obtained also by addition of hydrogen bromide to a l-alkene, also known as an alpha-olefin.

This addition of hydrogen bromide is effected preferably in the presence of peroxides or sunlight.

Alkyl halides, including straight chain alkyl halides utilizable in my process, may also be obtained by halogenating parafiins with chlorine or bromine. Thus n-hexane may be treated with chlorine to form n-hexyl chloride as indicated by Equation 1 as follows:

result from inter Another method which may be employed in manufacturing branched chain alkyl halides containing at least 6 carbon atoms per molecule involves the condensation of a relatively lowboiling alkyl halide with an olefin containing 2 or more carbon atoms per molecule. Thus, condensation of tertiary butyl chloride and ethylene yields chloroneohexane. Similarly, condensation of a mono-olefin and a relatively low boiling alkyl halide to produce a higher-boiling alkyl halide is effected in the presence of a catalyst of the Friedel-Crafts type, but the particular catalyst so employed is not necessarily the same as that preferably utilized in the further reaction of the higher-boiling alkyl halide with isobutane or isopentane to form a product containing a substantial amount of a branched chain paraffinic hydrocarbon having the same number of carbon atoms per molecule as were present in said higher-boiling alkyl halide.

The process of the present invention for reacting an alkyl halide containing at least 6 carbon atoms per molecule with a parafiinic hydrocarbon containing at least 4 and not more than 5 carbon atoms per molecule is carried out in the presence of a catalyst of the Friedel- Crafts type. Effective catalysts of the Friedel- Crafts type include aluminum chloride, aluminum bromide, zirconium chloride, zinc chloride, ferric chloride, boron fluoride, etc. tions of operation utilizable with these catalysts may be diiferent depending upon catalytic activities and other factors. These different cal-Talytic materials may be utilized as such, or they may be composited with one another, or some of them may be deposited upon solid carriers or supporting materials to produce catalyst composites of desired activities. Catalyst carriers or supports include both adsorptive and substantially non-adsorptive materials, including alumina, silica, activated charcoal, crushed porcelain, raw and acid-treated clays, diatomaceous earth, pumice, fire brick, etc. The carriers should be substantially inert in the sense that between catalyst and carrier, substantially no interaction occurs which is detrimental to the activity or selectivity of the catalyst composite.

The present processfcr producing a branched chain paraffinic hydrocarbon containing at least 6 carbon atoms per molecule may be illustrated by Equation 3 given below, which relates to a reaction between a branched chain heptyl chloride, (b1)-C7H15C1, and isobutane and results in the production of a branched chain heptane (br)-C'zH1e, isobutylene. and hydrogen chloride.

The net result of the reactions the two preceding equations may by Equation 5 as follows:

represented by be represented Under some conditions, part of the isobutylene formed as indicated above reacts with hydrogen chloride to form tertiary butyl chloride which The condimay be isolated as such. The tertiary butyl chloride may then be reacted with propylene to form a branched chain heptyl chloride suitable for charging to the process illustrated by Equation 3.

I believe my. process for producing branched chain parafiins by the reaction of a low molecular weight isoparaffin with an alkyl halide containing at least 6 carbon atoms per molecule in the presence of a Friedel-Crafts type catalyst will give a higher yield of branched chain paraffinic hydrocarbons than is obtained in the usual alkylation process. I believe also that my process will yield more desirable branched chain parafiinic gasoline of high octane number.

The alkylation of an isoparaffin with an olefin in the presence of a Friedel-Crafts type catalyst and a hydrogen halide as hydrogen chloride or hydrogen bromide seems to involve the formation of an alkyl halide corresponding in carbon structure to that of the isoparaflin. The alkyl halide then appears to react with the olefin to form a higher molecular weight alkyl halide which may be reacted further with a relatively low molecular weight isoparafiin under the conditions herein described to form a branched chain parafiin of gasoline boiling range and an alkyl halide containing the same number of carbon atoms per molecule as present in the relatively low-boiling parafiin. For example, the alkylation of isobutane with propylene in the presence of aluminum chloride and hydrogen chloride may involve the following steps:

Equation 6 illustrates the reaction of isobutane and propylene in the presence of aluminum chloride and hydrogen chloride whereby tertiary butyl chloride and propane are formed. The tertiary butyl chloride undergoes condensation with propylene, as illustrated by Equation 7, formin a heptyl chloride which may be designated as 2,2-dimethyl-4-chloropentane. The resultant chloroheptane then reacts with isobutane, as illustrated in Equation 8, to yield tertiary butyl chloride and a branched chain heptane, which is normally referred to as an alkylate.

omn n the reactions illustrated by Equations 7 and 8 to obtain good yields of products of high quality. Thus, for example, tertiary butyl chloride is reacted with propylene in the presence of any one of a number of metal Crafts type to yield a chloroheptane. The resultant chloroheptane is then reacted with an excess of isobutane in the presence of aluminum chloride, zirconium chloride, ferric chloride, etc, to. obtain heptane as a major product of the process; Isobutane is converted into tertiary butyl chloride which may be isolated as such when relatively mild reaction conditions are employed. but under more severe operating conditions, a substantial proportion of the tertia y butyl chloride reacts to form iso-octane and other paraffinic hydrocarbons.

. My process for reacting an alkyl halide containing at least 6 carbon atoms per molecule with a parafiinic hydrocarbon containing at least 4 and-not more than carbonatoms per molecule, and particularly with isobutane and isopentane inthe presence of a, catalyst of the Friedel-Crafts type, is carried out generally at a temperature of from about 40 to about +100 C. and preferably at a temperature of from about to about +100 C. The conditions of operation are so controlled as to form a branched chain paraliinic hydrocarbon fraction as the principal product of the process. It is desirable to have an excess of isobutane or isopentane admixed-with the. alkyl halide being reacted in the presence of the catalyst in order to obtain a. relatively high yield of branched chain paraffinic hydrocarbons and. to form lower boiling alkyl halides suitable for condensation with olefinic hydrocarbons to produce the higher boiling alkyl halides as hereinabove set forth.

The preferred operating temperature employed inmy process will depend upon several factors, including the halogen present in the alkyl halide, the type of alkyl halide utilized, and the nature of the parafiinic hydrocarbon which is being reacted with-the alkyl halide. Thus,- alkyl bromides can generally be utilized at a lower'reaction temperature than the corresponding alkyl chlorides. The various alkyl halides may also be employed under different conditions of operation, particularly because the tertiary alkyl halides are more reactive than secondary alkyl halides, and the latter, in turn, are more reactive than primary alkyl halides. Some parafiinic hydrocarbons are more reactive than others. Thus, isopentane appears to be more reactive than isobutane, and the latter reacts more readily than normal pentane or normal butane under the conditions of operation herein set forth.

The following examples are given to illustrate the process, although the data presented are not introduced with the intention of restricting unduly the broad scope of the invention.

Example I A solution of 21 parts by weight of 4-chloro-2, Zedimethylbutane and 77 parts by weight of isobutane was contacted with 5 parts by weight of aluminum chloride for one hour at C. in a glass-lined rotating autoclave. This treatment was followed by continuing the reaction at 40 C. for three hours. The resultant reaction product, after cooling to 20 0., consisted of parts by weight of liquid, 59 parts by weight of condensible gas comprising essentially isobutane, and 9 parts by weight of a sludge-likematerial chlorides of the Friedelwith a reddish brown color. A total of 4.5 parts by weight of hydrogen chloride was also obtained.

The liquor product consisted chiefly of isopentane, 2,3-dimethylbutane, and higher boiling paralfins. The presence of the 2,3-dimethyllbutanewas proven by preparing the c ystalline dibromide by photobromination.

Fifteen parts by weight is the theoretical yield of hexane to be expected from the 21 parts by weight of 4-chloro-2,2-dimethylbutane charged to the process. Since 25 parts by weight of liquid product was obtained, it appears that isobutane was converted into liquid paraffinic hydrocarbons.

Example II In another run similar to that described in Example I, a solution of 28 parts by weight of 4-chloro-,2-dimethylbutane and 50 parts by weight of isopentane were reacted in the presence of 4 parts by weight of substantially anhydrous aluminum chloride. The glass-lined autoclave containing the aforementioned materials was charged with nitrogen to 50' atmospherespressure and the autoclave was 'then rotated and heated at 50 C. for four hours. After this time of reaction, the autoclave was cooled and the reaction products were removed therefrom, The reaction product consisted of 45 parts by weight or" liquid product, 20 parts by Weight of a condensible gas fraction, 9 parts by weight of catalyst layer, and 4 parts by weight of hydrogen chloride. The condensible gas fraction was found to contain about 35 mole per cent of butanes, 60 per cent of pentanes, and 5 per cent of heXa'neS. At least 95 per cent of the" butanes and pentans were isobutane and isop'entane.

Distillation of the liquid it contained 35 parts by weight of liquid product boiling higher than isopentane. This liquid product included 12 parts by weight of hexanes containing 2,3-dimethylbutane and 11 parts by weight of an octane fraction. which contained from'about 15 to 45 per cent of chlorohexane.

Example III 21 parts by weight of 4-chloro-2,2-dimethylpentane (prepared by the condensation of tertiary butyl chloride with propylene) was added to parts by weight of isobutane and 10 parts by weight of alumimun chloride at 10 C. In this treatment, the 4-ch1oro-2,2-dimethylpentane was added dropwise during 45 minutes to the well-stirred mixture of isobutane and alupressure. lf he catalyst was converted into a yellow semi-solid, but substantially no hydrogen chloride was evolved. At this point 30 parts by weight of isopentane was added gradually, and

pleted in 30 minutes, and the stirring of the reaction mixture was then continued for one hour. The upper layer of reaction product was then decanted from the catalyst, washed with Water, dried, and'dist illed. All of the chloroheptane was consumed during the reaction. The recovered liquid product, which-was completely paraifinic, consisted of 24 parts by weight of paraffins containing 6 or more carbon atoms per molecule. The liquid product comprised heptanes as the largest fraction, but hexanes, octanes, nonanes, and decanes were present in somewhat smaller amounts.

product showed that Example IV When 44 parts by weight of propylene was added during 30 minutes to a stirred solution of 92 parts by weight of tertiary-butyl chloride in 120 parts by weight of isopentane at -25 C. in the presence of 20 parts by weight of aluminum chloride, the expected 4-ch1oro-2,2-dimethylpentane was formed together with small amounts of higher boiling materials but hydrogen chloride was not evolved and the aluminum chloride was converted into an orange colored, semi-solid material. The presence of 4-ch1oro-2,2-dimethylpentane in this reaction product was shown by analysis of a small portion of the total reaction product.

The temperature of the reaction mixture containing 4-chloro-2,Z-dimethylpentane was then permitted to increase slowly. Evolution of hydrogen chloride began when the temperature reached about -13 C. and became copious at a temperature of from 10 to 4 C., the latter temperature being reached after one hour, The stirring of the reaction mixture was continued for 1.5 hours at -4 to +2 0., when the evolution of hydrogen chloride had ceased. The reaction products included 28 parts by weight of hydrogen chloride, 136 parts by weight of liquid paraffins of higher molecular weight than pentane, and 57 parts by weight of a brown, viscous catalyst layer. The liquid consisted essentially of paraflinic hydrocarbons, but traces of chlorine-containing compounds were present as evidenced by the evolution of a small amount of hydrogen chloride during the early part of the distillation of the washed product. Hexanes, heptanes, and ootanes were the main products of the reaction, but substantial amounts of nonanes, decanes, and higher boiling hydrocarbons were obtained also. Similar results were obtained in another run, which was carried out by placing a similar mixture of propylene, tertiary butyl chloride, isopentane, and aluminum chloride in an autoclave which was then rotated at 20 C. for four hours and then permitted to stand over night before removing the products therefrom and separating them from the catalyst.

The character of the invention and the type of results obtained by its use are evident from the preceding specification and examples, although they are not to be construed as imposing undue limitations upon its broad scope.

I claim as my invention:

1. A process for preparing branched paraflinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises reducing an alkyl halide containing at least 6 carbon atoms per molecule by reacting said alkyl halide with an isoparaifmic hydrocarbon containing not more than 5 carbon atoms per molecule in the presence of a catalytic amount of a metal halide of the liriedel-Crafts type, said catalytic amount being less than the stoichiometric amount required to form a double compound with said alkyl halide but sufiicient to effect replacement of the halogen content of said alkyl halide with hydrogen, and recovering parafiinic reaction products comprising a branched chain parafiin hydrocarbon containing the same number of carbon atoms per molecule as said alkyl halide.

2. A process for preparing branched paraffinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises reducing an alkyl halide containing at least 6 carbon atoms per molecule by reacting said alkyl halide with an isoparafiinlc hydrocarbon containing not more than 5 carbon atoms per molecule in the presence of a catalytic amount ofsubstantially anhydrous aluminum chloride, said catalytic amount being less than the stoichiometric amount required to form a double compound with said alkyl halide but suflicient to effect replacement of the halogen content of said alkyl halide with hydrogen, and recovering paraffinic reaction products comprising a branched chain paraffin hydrocarbon containing the same number of carbon atoms per molecule as said alkyl halide.

3. A process for preparing branched parafiinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises reducing an alkyl halide containing at least 6 carbon atoms per molecule by reacting said alkyl halide'at a temperature of from about -40 to about C. with an isoparaflinic hydrocarbon containing not more than 5 carbon atoms per molecule in the presence of a catalytic amount of a metal halide of the Friedel-Crafts type, said catalytic amount being less than the stoichiometric amount required to form a double compound with said alkyl halide but suflicient to effect replacement of the halogen content of said alkyl halide with hydrogen, and recovering paraflinic reaction products comprising a branched chain paraifin hydrocarbon containing the same number of carbon atoms per molecule as said alkyl halide.

4. A process for preparing branched parafiinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises reducing an alkyl halide containing at least 6 carbon atoms per molecule by reacting said alkyl halide at a temperature of from about -10 to about 100 C. with an isoparaflinic hydrocarbon containing not more than 5 carbon atoms per molecule in the presence of a catalytic amount of substantially anhydrous aluminum chloride, said catalytic amount being less than the stoichiometric amount required to form a double compound with said alkyl halide but sufficient to efiect replacement of the halogen content of said alkyl halide with hydrogen, and recovering parafiinic reaction products comprising a branched chain paraffin hydrocarbon containing the same number of carbon atoms per molecule as said alkyl halide.

5. A process for preparing branched paraflinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises reducing -chloro- 2,2-dimethylbutane by reacting said compound with isobutane at a temperature of from about -l0 to about 100 C. in the presence of a catalytic amount of aluminum chloride, said catalytic amount being less than the stoichiometric amount required to form a double compound with said 4-chloro-2,Z-dimethylbutane but sufiicient to effect replacement of the chlorine content of said 4-chloro-2,2-dimethylbutane with hydrogen, and recovering paraflinic reaction products comprising a branched chain paraflin hydrocarbon containing the same number of carbon atoms per molecule as said 4-chloro2,2-dimethylbutane.

G. A process for preparing branched paratfinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises reducing ii-chloro- 2,2-dimethylbutane by reacting said compound with isopentane at a temperature of from about -10 to about 100 C. in the presence of a catalytic amount of aluminum chloride, said catalytic amount being less than the stoichiometric amount required to form a double compound with said 4-chloro-2,2-dimethylbutane but suificient to effect replacement or the chlorine content of said 9 4-chloro-2,2-dimethylbutane with hydrogen, and recovering parafiinic reaction products comprising a branched chain paraffin hydrocarbon containing the same number of carbon atoms per molecule as said 4-chloro-2,Z-dimethylbutane.

'7. A process for preparing branched paraffinic hydrocarbons containing at least 6 carbon atoms per molecule, which comprises condensing an alkyl halide and an olefin in the presence of a catalyst of the Friedel-Crafts type to form a mono-haloalkane containing at least 6 carbon atoms per molecule, reducing said mono-haloalkane by reaction with an isoparafiinic hydrocarbon containing not more than 5 carbon atoms per molecule at a temperature of from about 10 to about 100 C. in the presence of a catalytic amount of a metal halide of the Friedel-Crafts type, said catalytic amount being less than the stoichiometric amount required to form a double compound with said mono-haloalkane but sulficient to efiect replacement of the halogen content of said mono-haloalkane with hydrogen, and recovering paraffinic reaction products comprising a branched chain paraffin hydrocarbon containing the same number molecule as said mono-haloalkane.

8. A process for preparing branched paraffinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises condensing an alkyl halide and an olefin at a temperature of from about 40 to about C. in the presence of a catalyst of the Friedel-Crafts type to form a mono-haloalkane containing at least 6 carbon atoms per molecule, reducing said mono-haloalkane by reaction with an isoparafiimc hydrocarbon containing not more than carbon atoms per molecule at a temperature of from about 10 to about 100 C. in the presence of a catalytic amount of a metal halide of the Friedel-Crafts type, said catalytic amount being less than the stoichiometric amount required to form a double compound with said mono-haloalkane but being sufiicient to effect replacement of the halogen content of said mono-haloalkane with hydrogen, separating from the resultant products a branched chain paraffin having the same number of carbon atoms per molecule as said monohaloalkane and an alkyl halide having the same number of carbon atoms per molecule as said isoparaffinic hydrocarbon, recovering said branched chain paralfin, and recycling said last-named alkyl halide to condensation with said olefin.

9. A process for preparing branched parafiinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises condensing a tertiary alkyl halide and an olefin at a temperature of from about 40 to about 10 C. in the presence of an aluminum chloride catalyst for a time sufiicient to produce a mono-haloalkane containing at least 6 carbon atoms per molecule as the principal reaction product, reducing said monoof carbon atoms per haloalkane by warming said reaction product in the presence of said aluminum chloride catalyst and an isoparaffinic hydrocarbon containing at least 4 and not more than 5 carbon atoms per molecule to a temperature of from about l0 to about C., said aluminum chloride catalyst being present in an amount less than the stoichiometric amount required to form a double compound with said mono-haloalkane but sufficient to efiect replacement of the halogen content of said monohaloalkane with hydrogen, and recovering paraffinic reaction products comprising a branched chain paraflin hydrocarbon containing the same number of carbon atoms per molecule as said mono-haloalkane.

10. A process for preparing branched paraflinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises condensing tertiary butyl chloride and propylene at a temperature of from about -40 to about 10 C. in the presence of an aluminum chloride catalyst for a time sufilcient to produce 4-chloro-2,2-dimethylpentane as the principal reaction product, reducing said 4-chloro-2,2-dimethylpentane by warming said reaction product in the presence of said aluminum chloride catalyst and isopentane to a temperature of from about 10 to about 100 C., said aluminum chloride catalyst being present in an amount less than the stoichiometric amount required to form a double compound with said 4- chloro-2,2-dimethylpentane but suflicient to effect replacement of the halogen content of said 4-chloro-2,2-dimethylpentane with hydrogen, and recovering paraifinic reaction products comprising a branched chain parafiin hydrocarbon containing the same number of carbon atoms per molecule as said 4-chloro-2,2-dimethylpentane.

11. A process for preparing branched paraflinic hydrocarbons containing at least 6 carbon atoms per molecule which comprises condensing tertiary butyl chloride and propylene at a temperature of from about 40 to about 10 C. in the presence of an aluminum chloride catalyst for a time sufficient to produce 4-chloro-2,2-dimethylpentane as the principal reaction product, reducing said 4-chloro-2,2-dimethylpentane by warming said reaction product in the presence of said aluminum chloride catalyst and isobutane to a temperature of from about 10 to about 100 0., said aluminum chloride catalyst being present in an amount less than the stoichiometric amount required to form a double compound with said 4- ohloro-2,2-dimethylpentane but sufficient to effect replacement of the halogen content of said 4-chloro-2,2-dimethylpentane with hydrogen, and recovering paraflinic reaction products comprising a branched chain paraffin hydrocarbon containing the same number of carbon atoms per molecule as said 4-chloro-2,2-dimethylpentane.

LOUIS SCI-HEERLING. 

